Bidirectional dc/dc converters are gaining more attentions due to the recent rapid development in renewable energy harvesting technologies. FIG. 1 shows an exemplary renewable energy system 100. In FIG. 1, the renewable energy system 100 includes different components for harvesting renewable energy. For example, the system includes a wind turbine 102 for harvesting winding energy and a photovoltaic panel 104 for harvesting light energy. In general, these renewable energy has to be converted to a relatively stable dc link voltage before it can be further converted to different dc or ac voltages for use. In the present example, the wind turbine 102 is connected to a dc link 106 through a Permanent Magnet synchronous Generator 108 and an ac-dc converter 110, whilst the photovoltaic panel 104 is connected to the dc link 106 via a dc-dc converter 112. The energy provided by these sources, collected at the dc link 106, will either be used or stored. For example, the energy may be provided through a dc-ac converter 114 to a grid 116 or ac load 118 for use. The energy may also be stored in an energy storage system 120, which includes, for example, a battery stack 122 and a super-capacitor 124, through a dc-dc converter 126. Ideally, the dc-dc converter 126 of the energy storage system 120 allows bi-directional energy transfer between the dc link 106 and the battery stack 122/super-capacitor 124, and can process bidirectional power flow efficiently even under wide variations in power level and/or voltage levels on both sides.